Semiconductor device and method for manufacturing the semiconductor device

ABSTRACT

A semiconductor device is disclosed in which an implant board and a semiconductor element of a semiconductor mounting board are bonded and electrically connected through implant pins and which can be manufactured with high productivity. Implant pins are bonded to a semiconductor element and/or a circuit pattern of a semiconductor mounting board through cylindrical terminals press-fitted into the other ends of the implant pins. Press-fitting depth L 2  of each of the implant pins into corresponding cylindrical terminals is adjustable, so that total length of the implant pin and cylindrical terminal which are press-fitted to each other matches up with the distance between the semiconductor element and/or the circuit pattern on the semiconductor mounting board and an implant board.

BACKGROUND OF THE INVENTION

A. Field of the Invention

The present invention relates to a semiconductor device and a method formanufacturing the same. Particularly, it relates to a semiconductordevice mounted with power semiconductor elements etc. and a method formanufacturing the semiconductor device.

B. Description of the Related Art

An example of a semiconductor device in which semiconductor elements aremodularized has a package structure shown in FIG. 9. In thesemiconductor device shown in FIG. 9, cooling plate 51 is arranged in abottom portion of resin casing 52. Insulating wiring board 56 isarranged on cooling plate 51. Insulating wiring board 56 is configuredin such a manner that metal layers 54 and 55 are bonded to oppositesurfaces of insulating substrate 53. Metal layer 55 of insulating wiringboard 56 and cooling plate 51 are bonded to each other through solderlayer 57 a. Semiconductor elements 58 are arranged on insulating wiringboard 56. Metal layer 54 of insulating wiring board 56 and semiconductorelements 58 are bonded to each other through solder layer 57 b. Inaddition, external terminals 59 are arranged on insulating wiring board56. Metal layer 54 of insulating wiring board 56 and external terminals59 are bonded to each other through solder layer 57 c. Semiconductorelements 58 are electrically connected to external terminals 59respectively by bonding wires 60. The inside of resin casing 52 isfilled and sealed with sealing resin 61.

High heat dissipation is required articularly in the case ofsemiconductor elements which generate significant heat, like powersemiconductor elements such as IGBTs (Insulated Gate Bipolar Transistor)etc, However, in such a semiconductor device according to the backgroundart, bonding wires 60, for example, consisting of thin aluminum wireseach having a wire diameter of about 300 μm to 400 μm are only connectedto the upper surface sides of ss semiconductor elements 58. Moreover,since heat is generated in accordance with electricity passing throughbonding wires 60, it is almost impossible to obtain any heat dissipationeffect from the upper surface sides of semiconductor elements 58.

A method for improving wiring current density, fusing currentresistance, bonding reliability, heat dissipation, etc. has beendescribed in PTL 1 and PTL 2. In PTL 1 and PTL 2, an implant board andsemiconductor elements of a semiconductor mounting board are bonded toeach other through implant pins in place of the wire bonding wiringstructure.

A semiconductor device disclosed in PTL 1 will be described withreference to FIGS. 10 and 11. Incidentally, portions substantially thesame as those in the semiconductor device shown in FIG. 9 are referredto by corresponding numerals, so that description thereof will beomitted.

In the semiconductor device shown in FIG. 10, semiconductor elements 58are arranged on insulating wiring board 56. Metal layer 54 of insulatingwiring board 56 and semiconductor elements 58 are bonded to each otherthrough solder layer 57 b.

Implant board 79 is arranged above semiconductor elements 58. Implantboard 79 and semiconductor elements 58 are electrically connected toeach other through implant pins 76 of implant board 79.

Implant board 79 includes insulating wiring board 75, and implant pins76 press-fitted into via holes 74. Insulating wiring board 75 isconfigured in such a manner that metal layers 72 and 73 forming aprinted wiring are bonded to opposite surfaces of insulating substrate71. Via holes 74 are formed to penetrate insulating substrate 71, metallayer 72 and metal layer 73 of insulating wiring board 75. Referring nowto FIG. 11, collar portion 77 is provided in each implant pin 76. Aconstant quantity between one end of the implant pin and collar portion77 is press-fitted into via hole 74. Collar portion 77 and insulatingwiring board 75 are bonded to each other through bonding material 78 a.Moreover, the other end of implant pin 76 is bonded to insulating wiringboard 56 or semiconductor element 58 through bonding material 78 b

-   PTL 1: JP-A-2011-82303-   PTL 2: WO 2011/083737

SUMMARY OF THE INVENTION

However, when the component configuration in the semiconductor deviceshown in FIG. 10 is changed for each kind of product so that the heightsof components including the semiconductor elements etc. are changed, itis necessary to adjust the length of each implant pin in accordance withthe distance between the semiconductor element and the implant board ineach bonding place. Therefore, it is necessary to prepare a number ofimplant boards in accordance with the number of the kinds of products,so that time and labor are required for inventory management of thesecomponents. In addition, a plurality of kinds of implant boards must beprepared in accordance with the kinds of products, so that the componentcost increases.

Therefore, the present invention provides a semiconductor device inwhich an implant board and semiconductor elements of a semiconductormounting board are bonded and electrically connected through implantpins and which can be manufactured with high productivity, and providesa method for manufacturing the semiconductor device.

The semiconductor device according to the invention is characterized inthat the implant pins are bonded to a semiconductor element and/or acircuit pattern of the semiconductor mounting board through cylindricalterminals press-fitted onto the other ends of the implant pins, and thedepth with which each of the implant pins is press-fitted intocorresponding one of the cylindrical terminals can be adjusted so thattotal length of the implant pin and the cylindrical terminal which arepress-fitted to each other can match up with a distance between thesemiconductor element and/or the circuit pattern on the semiconductormounting board and the implant board.

In the semiconductor device according to the invention, the implant pinsare bonded to the semiconductor element and/or the circuit pattern ofthe semiconductor mounting board through the cylindrical terminalspress-fitted onto the other ends of the implant pins. Therefore, thedepth with which each of the implant pins is press-fitted intocorresponding one of the cylindrical terminals can be adjusted so thatthe total length of the implant pin and the cylindrical terminal whichare press-fitted to each other can match up with the distance betweenthe semiconductor element and/or the circuit pattern on thesemiconductor mounting board and the implant board. Accordingly, evenwhen the distance between the semiconductor element and/or the circuitpattern on the semiconductor mounting board and the implant boarddiffers from one bonding portion to another, it is not necessary toprepare implant pins whose lengths match up with bonding portionsindividually. That is, it is not necessary to change the kind of theimplant board in accordance with each kind of product, but the implantboard can be used in common among a plurality of products. Therefore,inventory management of the components can be easy and the componentcost can be suppressed. Thus, the productivity is excellent.

In the semiconductor device according to the invention, a plating layermay be provided in a surface of a press-fitting portion of each of theimplant pins into corresponding one of the cylindrical terminals and/oran inner circumferential surface of the cylindrical terminal.Preferably, the implant pin press-fitted into the cylindrical terminalis heated to melt the plating layer so that a contact portion betweenthe implant pin and the cylindrical terminal can be bonded to each otherby the plating layer.

In the semiconductor device according to the invention, a sintermaterial may be applied to a surface of a press-fitting portion of eachof the implant pins into corresponding one of the cylindrical terminalsand/or an inner circumferential surface of the cylindrical terminal.Preferably, the implant pin press-fitted into the cylindrical terminalis heated to sinter the sinter material so that a contact portionbetween the implant pin and the cylindrical terminal can be bonded toeach other.

According to the aforementioned aspects, the bonding strength betweeneach of the implant pins and corresponding one of the cylindricalterminals is so high that the bonding reliability is excellent.

In the semiconductor device according to the invention, preferably, eachof the implant pins is in contact with at least 40% of an innercircumference of corresponding one of the cylindrical terminals in asection perpendicular to the implant pin in a contact portion betweenthe implant pin and an inner circumferential surface of the cylindricalterminal. According to this aspect, the conductivity is excellent.Furthermore, the bonding strength between the implant pin and thecylindrical terminal is high, and the bonding reliability is excellent.

In the semiconductor device according to the invention, preferably, aprotruding portion which protrudes over an outer circumference of eachof the implant pins is provided in a press-fitting portion of theimplant pin into corresponding one of the cylindrical terminals bydrawing, so that the protruding portion can come into contact with aninner circumferential surface of the cylinder terminal. In this aspect,preferably, a value obtained by subtracting an inner diameter of each ofthe cylindrical terminals from a largest diameter of a press-fittingportion of corresponding one of the implant pins which has not yet beenpress-fitted is in the range of from 0 to 0.25 mm.

In the semiconductor device according to the invention, preferably, astraight columnar portion which is not subjected to drawing is providedin a press-fitting portion of each of the implant pins so that at leasta part of the columnar portion can come into contact with an innercircumferential surface of corresponding one of the cylindricalterminals. In this aspect, preferably, a value obtained by subtractingan inner diameter of each of the cylindrical terminals from a largestdiameter of a press-fitting portion of corresponding one of the implantpins which has not yet been press-fitted is in the range of from 0 to0.15 mm.

According to the aforementioned aspects, the bonding strength betweeneach of the implant pins and corresponding one of the cylindricalterminals is high and the bonding reliability is excellent.

In the semiconductor device according to the invention, preferably, eachof the implant pins has a tapered end on the cylindrical terminal sideso that the implant pin has a diameter which decreases toward the end.According to this aspect, an operation of press-fitting the implant pininto the cylindrical terminal becomes easy.

In the semiconductor device according to the invention, preferably, aninner circumference of each of the cylindrical terminals is formed intoa shape which matches up with a press-fitting portion of correspondingone of the implant pins. In this aspect, the contact area of the implantpin with the inner circumference of the cylindrical terminal can beincreased. Thus, the conductivity and the bonding strength areexcellent.

In addition, the semiconductor device manufacturing method according tothe invention is a method for manufacturing a semiconductor device,including the steps of: preparing a semiconductor mounting board inwhich a semiconductor element is mounted on an insulating wiring board;preparing an implant board in which via holes for electric connectionare provided in an insulating substrate having a printed wiring and oneends of implant pins are press-fitted into the via holes; and bondingthe other ends of the implant pins of the implant board to thesemiconductor element and/or a circuit pattern of the semiconductormounting board so as to make electric connection to the semiconductorelement of the semiconductor mounting board; characterized in that: eachof cylindrical terminals is press-fitted onto the other end ofcorresponding one of the implant pins and depth with which thecylindrical terminal is press-fitted is adjusted so that length of theimplant pin can match up with a distance between the semiconductorelement and/or the circuit pattern on the semiconductor mounting boardand the implant board and the implant pin can be bonded to thesemiconductor element and/or the circuit pattern of the semiconductormounting board through the cylindrical terminal.

In the semiconductor device manufacturing method according to theinvention, a plating layer may be formed in a surface of a press-fittingportion of each of the implant pins into corresponding one of thecylindrical terminals and/or an inner circumferential surface of thecylindrical terminal. The other end of the implant pin of the implantboard is made to abut against the semiconductor element and/or thecircuit pattern of the semiconductor mounting board through the cylinderterminal and the semiconductor device thus assembled is heated in areflow furnace in this state. Thus, connection is made between thesemiconductor element and the insulating wiring board and connection ismade between the cylindrical terminal corresponding to the implant pinand the semiconductor element and/or the circuit pattern of thesemiconductor mounting board. In addition thereto, preferably, theplating layer is melted to thereby connect the implant pin and thecylindrical terminal to each other.

In the semiconductor device manufacturing method according to theinvention, a sinter material may applied in a surface of a press-fittingportion of each of the implant pins into corresponding one of thecylindrical terminals and/or an inner circumferential surface of thecylindrical terminal. The other end of the implant pin of the implantboard abuts against the semiconductor element and/or the circuit patternof the semiconductor mounting board through the cylinder terminal andthe semiconductor device thus assembled is heated in a reflow furnace inthis state. Thus, connection is made between the semiconductor elementand the insulating wiring board and connection is made between thecylindrical terminal corresponding to the implant pin and thesemiconductor element and/or the circuit pattern of the semiconductormounting board. In addition thereto, preferably, the sinter material issintered to thereby connect the implant pin and the cylindrical terminalto each other.

According to the invention, the implant board can be used in commonamong a plurality of products. Accordingly, inventory management of thecomponents can be performed easily and the component cost can besuppressed so that a semiconductor device in which semiconductorelements are electrically connected by the implant board can bemanufactured with high productivity.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing advantages and features of the invention will becomeapparent upon reference to the following detailed description and theaccompanying drawings, of which:

FIG. 1 is a schematic sectional view showing an embodiment of asemiconductor device according to the invention;

FIG. 2 is an enlarged view of a portion A in FIG. 1;

FIGS. 3( a) and 3(b) are a schematic view of an external terminal whichcan be used in the semiconductor device, in which 3(a) is a side viewand 3(b) is a sectional view taken along the line C-C in 3(a);

FIGS. 4( a) and 4(b) are a schematic view of an external terminal whichcan be used in the semiconductor device, in which 4(a) is a side viewand 4(b) is a sectional view taken along the line D-D in 4(a);

FIGS. 5( a) and 5(b) are a schematic view of an external terminal whichcan be used in the semiconductor device, in which 5(a) is a side viewand 5(b) is a sectional view taken along the line E-E in 5(a);

FIGS. 6( a) and 6(b) are a schematic view of an external terminal whichcan be used in the semiconductor device, in which 6(a) is a side viewand 6(b) is a sectional view taken along the line F-F in 6(a);

FIG. 7 is an important part enlarged sectional view showing anotherembodiment of the semiconductor device according to the invention;

FIG. 8 is an important part enlarged sectional view showing furtheranother embodiment of the semiconductor device according to theinvention;

FIG. 9 is a schematic sectional view showing an example of asemiconductor device according to the background art;

FIG. 10 is a schematic sectional view showing another example of thesemiconductor device according to the background art;

FIG. 11 is an enlarged view of a portion G in FIG. 10;

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

A semiconductor device according to the invention will be described withreference to the drawings. An embodiment of the semiconductor deviceaccording to the invention is shown in FIG. 1.

In the semiconductor device, cooling plate 1 is arranged in a bottomportion of resin casing 2. Cooling plate 1 is made of a material havinghigh heat dissipation. For example, copper, aluminum, a copper alloy, analuminum alloy, etc. may be used as the material of cooling plate 1.

Insulating wiring board 3 is arranged on cooling plate 1. Insulatingwiring board 3 is formed in such a manner that metal layers 5 and 6 arebonded to opposite surfaces of insulating substrate 4. A predeterminedcircuit pattern is formed on insulating substrate 4 by metal layer 5.Metal layer 6 of insulating wiring board 3 and cooling plate 1 arebonded through a solder or sinter material layer 7 a.

There is no particular limitation on insulating wiring board 3. Forexample, a direct bonding copper board in which a copper plate is bondeddirectly on a ceramic substrate, an active metal brazed copper board inwhich ceramics and a copper plate are bonded through a brazing material,or the like, may be used as insulating wiring board 3.

External terminals 9 are bonded to predetermined places of metal layer 5forming the circuit pattern of insulating wiring board 3, through asolder or sinter material layer 7 b. In addition, a plurality ofsemiconductor elements 8 a and 8 b are bonded to the same metal layer 5through a solder or sinter material layer 7 c. Each of semiconductorelements 8 a and 8 b varies according to use purposes. For example, apower semiconductor element such as an IGBT, a rectifier element such asan FWD, etc. may be used as semiconductor element 8 a, 8 b.

Implant board 30 is disposed above semiconductor element 8. Implantboard 30 includes insulating wiring board 34, and implant pins 20press-fitted into via holes 35. Insulating wiring board 34 is configuredin such a manner that metal layers 32 and 33 forming a printed wiringare bonded to opposite surfaces of insulating substrate 31. Each of viaholes 35 is formed to penetrate metal layer 32, insulating substrate 31and metal layer 33 of insulating wiring board 34. A metal layer(not-shown) connected conductively to metal layer 32 and/or metal layer33 is formed in an inner surface of each of via holes 35. The metallayer in the inner surface is connected conductively to implant pin 20.

Lower ends of some of implant pins 20 of implant board 30 arepress-fitted into cylindrical terminals 10. In the embodiment, implantpins 20 which do not have cylindrical terminals 10 are connected tosemiconductor element 8 a through a solder or sinter material layer 7 e.Moreover, cylindrical terminals 10 in implant pins 20 having cylindricalterminals 10 are connected to semiconductor element 8 b and metal layer5 through a solder or sinter material layer 7 d.

Referring now to FIG. 2, collar portion 26 is provided in each ofimplant pins 20. A constant quantity L1 between end 27 of each implantpin and collar portion 26 is press-fitted into pin hole 35. Each ofcollar portions 26 and insulating wiring board 34 are bonded throughbonding material 36.

Press-fitting depth L2 of each of implant pins 20 into cylindricalterminals 10 is adjusted for each cylindrical terminal so as to match upwith the distance between semiconductor element 8 b and implant board 30and the distance between metal layer 5 and implant board 30.

That is, an implant board provided with implant pins having differentlengths in accordance with the distance between semiconductor element 8and implant board 30 and the distance between metal layer 5 and implantboard 30 is not used in the invention. According to the invention, thepress-fitting depth of each implant pin 20 into a correspondingcylindrical terminal 10 is changed in accordance with each of thedistances. Thus, implant board 30 is bonded to semiconductor element 8or metal layer 5 to make electric connection for each of thesemiconductor elements. Therefore, it is not necessary to change theimplant board in accordance with each kind of product so that theimplant board can be used in common among a plurality of products.

Incidentally, when the distance between implant board 30 andsemiconductor element 8 or metal layer 5 matches up with the length ofeach implant pin 20 extending from implant board 30, implant pin 20 maybe bonded to semiconductor element 8 or metal layer 5 not throughcylindrical terminal 10. In the embodiment, the distance between implantboard 30 and semiconductor element 8 a matches up with the length ofeach implant pin 20 extended from implant board 30, so that implant pin20 is bonded directly to semiconductor element 8 a through a solder orsinter material layer 7 e.

In the semiconductor device according to the invention, it is preferablethat each implant pin 20 is in contact with 40% or more of the innercircumference of cylindrical terminal 10 in a section taken along theline B-B in FIG. 2. The section taken along the line B-B in FIG. 2 is asection in a direction perpendicular to implant pin 20, in a contactportion between implant pin 20 and the inner circumference ofcylindrical terminal 10. When the contact area of implant pin 20 withcylindrical terminal 10 is smaller than 40%, bonding strength orconductivity may be insufficient. When the contact area is not smallerthan 40%, sufficient bond strength and conductivity can be obtained.

In the semiconductor device according to the invention, there is noparticular limitation on the shape of implant pin 20. An implant pinhaving any shape such as a cylindrical shape or a prismatic shape can beused as implant pin 20. For example, any of the shapes shown in FIGS. 3to 6 may be preferably used as the shape of the press-fitting portion ofimplant pin 20 into cylindrical terminal 10.

Implant pin 20 a shown in FIG. 3 is provided with a press-fittingportion consisting of straight columnar portion 21 which is notsubjected to drawing, and reduced diameter portion 23 whose diameter isreduced like a taper from the press-fitting portion toward end 25. Whenimplant pin 20 a is press-fitted into cylindrical terminal 10, columnarportion 21 comes into contact with the inner circumferential surface ofcylindrical terminal 10, so that columnar portion 21 and cylindricalterminal 10 are bonded to each other. Moreover, since end 25 has areduced diameter like a taper, the center position can be adjustedeasily when implant pin 20 a is press-fitted into cylindrical terminal10. Thus, the press-fitting is performed easily.

The largest outer diameter R_(max) of the press-fitting portion ofimplant pin 20 which has not yet been press-fitted is set so that adifference (R_(max)−R) between the largest outer diameter R_(max) and aninner diameter R of cylindrical terminal 10 is preferably in the rangeof from 0 to 0.15 mm. In addition, the difference (R_(max)−R) betweenthe largest outer diameter R_(max) and the inner diameter R ofcylindrical terminal 10 is more preferably in the range of from 0.05 mmto 0.15 mm, especially preferably in the range of from 0.05 mm to 0.10mm. When the largest outer diameter R_(max) is set such that thedifference is within the aforementioned range, implant pin 20 a can bepress-fitted into cylindrical terminal 10 without causing any damage inimplant pin 20 a, any damage in cylindrical terminal 10, etc. so thatimplant pin 20 a and cylindrical terminal 10 can be bonded to each otherfirmly.

Each of implant pins 20 b to 20 d shown in FIGS. 4 to 6 is provided witha press-fitting portion having protruding portion 22 protruding over theouter circumference due to drawing, and reduced diameter portion 23whose diameter is reduced like a taper from the press-fitting portiontoward end 25. In implant pin 20 b shown in FIG. 4, protruding portion22 is formed into a cross shape in section. In implant pin 20 c shown inFIG. 5, protruding portion 22 is formed into a Y-shape in section (ashape having three protruding parts protruding radially at equalangles). In implant pin 20 d shown in FIG. 6, protruding portion 22 isformed into a flat plate shape. When the implant pin is press-fittedinto cylindrical terminal 10, protruding portion 22 comes into contactwith the inner circumferential surface of cylindrical terminal 10 sothat protruding portion 22 and cylindrical terminal 10 are bonded toeach other. Moreover, since end 25 is reduced in diameter like a taper,the center position can be adjusted easily when implant pin 20 ispress-fitted into cylindrical terminal 10. Thus, the press-fitting canbe performed easily. Incidentally, the shape of the protruding portionformed by drawing is not limited to any of the shapes shown in FIGS. 4to 6.

The largest outer diameter R_(max) of the press-fitting portion in eachof implant pins 20 b to 20 d which has not yet been press-fitted is setso that a difference (R_(max)−R) between the largest outer diameterR_(max) and the inner diameter R of cylindrical terminal 10 ispreferably in the range of from 0 to 0.25 mm. Moreover, the difference(R_(max)−R) between the largest outer diameter R_(max) and the innerdiameter R of cylindrical terminal 10 is more preferably in the range offrom 0.05 mm to 0.25 mm, particularly preferably in the range of from0.10 mm to 0.20 mm. When the largest outer diameter R_(max) is set sothat the difference is within the aforementioned range, the implant pincan be press-fitted into cylindrical terminal 10 without causing anydamage in the implant pin, any damage in cylindrical terminal 10, etc.so that the implant pin and cylindrical terminal 10 can be bonded toeach other firmly.

The inner circumference of cylindrical terminal 10 is preferably shapedlike a hole which matches up with the press-fitting portion of implantpin 20. Since the inner circumference of cylindrical terminal 10 isformed into a shape which matches up with the press-fitting portion ofimplant pin 20, the contact area of implant pin 20 with the innercircumference of cylindrical terminal 10 can be made large. In addition,the ends of protruding portions 22 engage with the inner circumferencesof cylindrical terminals 10 respectively so as to prevent rotation.

The inside of resin casing 2 in the semiconductor device according tothe invention is filled and sealed with sealing resin 15 such as a gelor an epoxy resin.

Next, an embodiment of a semiconductor device manufacturing methodaccording to the invention will be described as a method formanufacturing the aforementioned semiconductor device.

First, a method for manufacturing implant board 30 will be described.Implant board 30 is manufactured as follows. Via holes 35 for electricconnection are formed in predetermined positions of insulating wiringboard 34 so as to penetrate metal layer 32, insulating substrate 31 andmetal layer 33. After ends 27 of implant pins 20 are press-fitted intovia holes 35, collar portions 26 of implant pins 20 and insulatingwiring board 34 are bonded by bonding material 36.

The method for manufacturing the semiconductor device will be describedbelow.

Insulating wiring board 3 is disposed on cooling plate 1 so that metallayer 6 side of insulating wiring board 3 can come into contact withcooling plate 1 through a solder or sinter material layer 7 a. Moreover,semiconductor elements 8 a and 8 b are disposed on a predeterminedcircuit pattern of metal layer 5 of insulating wiring board 3 through asolder or sinter material layer 7 c.

Next, implant pins 20 extending from implant board 30 are press-fittedinto cylindrical terminals 10. The press-fitting depth of each ofimplant pins 20 is adjusted so that the length of implant pin 20 canmatch up with the distance between semiconductor element 8 b and implantboard 30 or the distance between metal layer 5 and implant board 30.

Implant board 30 is disposed above insulating wiring board 3.Cylindrical terminals 10 are disposed in predetermined positions ofsemiconductor element 8 b and metal layer 5 through a solder or sintermaterial layer 7 d. In addition thereto, implant pins 20 extending fromimplant board 30 are disposed on semiconductor element 8 a through asolder or sinter material layer 7 e.

The semiconductor device is introduced into a reflow furnace in thisstate so that the solder or sinter material layers 7 a, 7 c, 7 d and 7 eare melted or sintered. Thus, cooling plate 1 and metal layer 6 ofinsulating wiring board 3 are bonded to each other. At the same time,bonding between semiconductor elements 8 a and 8 b and metal layer 5 ofinsulating wiring board 3, bonding between cylindrical terminals 10 andmetal layer 5 of insulating wiring board 3, bonding between cylindricalterminals 10 and semiconductor element 8 b and bonding between implantpins 20 and semiconductor element 8 a are performed.

The heating temperature in the reflow time is preferably not higher than350° C., more preferably in the range of from 250° C. to 330° C. Whenthe heating temperature is higher than 350° C., there is a fear that thesemiconductor elements etc. may be thermally damaged.

Next, external terminals 9 are disposed in predetermined positions ofmetal layer 5 through a solder or sinter material layer 7 b. The solderor sinter material layer 7 b is melted or sintered to bond externalterminals 9 and metal layer 5 to each other. Cooling plate 1 issurrounded by resin casing 2. The inside enclosed by resin casing 2 isfilled with sealing resin 15. The sealing resin is hardened. In thismanner, the semiconductor device according to the invention ismanufactured.

Another embodiment of the semiconductor device according to theinvention is shown in FIG. 7. In the semiconductor device, plating layer28 is provided in the surface of the press-fitting portion of eachimplant pin 20 into cylindrical terminal 10. When plating layer 28 ismelted, the press-fitting portion of implant pin 20 and the innercircumferential surface of cylindrical terminal 10 are bonded to eachother. Incidentally, in the embodiment, the plating layer is formed inthe surface of the press-fitting portion of implant pin 20.Alternatively, the plating layer may be formed in the innercircumferential surface of cylindrical terminal 10 or may be formed inboth the surface of the press-fitting portion of implant pin 20 and theinner circumferential surface of cylindrical terminal 10.

The thickness of plating layer 28 is preferably not larger than 5 μmprior to press-fitting. Plating layer 28 may be a single layer or may bea laminate of a plurality of plating layers. A layer or a laminate inwhich at least the outermost layer can be melted at a temperature nothigher than 350° C. is preferably used. Sn plating, SnAg-based solderplating, SnBi-based solder plating, SnSb-based solder plating,SnCu-based solder plating, Sn In-based solder plating, etc. may be usedas the plating material whose melting temperature is not higher than350° C. When the melting temperature is not higher than 350° C., theplating material can be melted in the reflow process for soldering thesemiconductor elements etc.

Next, another embodiment of a semiconductor device manufacturing methodaccording to the invention will be described as a method formanufacturing the aforementioned semiconductor device. In theembodiment, implant pins 20 extending from implant board 30 arepress-fitted into cylindrical terminals 10 and the press-fitting depthof each of implant pins 20 is adjusted, in the same manner as in theaforementioned embodiment. In this manner, the length of each of implantpins 20 matches up with the distance between semiconductor element 8 band implant board 30 or the distance between metal layer 5 and implantboard 30. Cylindrical terminals 10 are disposed in predeterminedpositions of semiconductor element 8 b and metal layer 5 through thesolder or sinter material layer 7 d. Moreover, implant pins 20 extendingfrom implant board 30 are disposed on semiconductor element 8 a throughthe solder or sinter material layer 7 e.

The semiconductor device is introduced into a reflow furnace in thisstate so that the solder or sinter material layers 7 a, 7 c, 7 d and 7 eand plating layer 28 are melted or sintered. Thus, through the solder orsinter material layers 7 a, 7 c, 7 d and 7 e, cooling plate 1 and metallayer 6 of insulating wiring board 3 are bonded to each other. At thesame time, bonding between semiconductor elements 8 a and 8 b and metallayer 5 of insulating wiring board 3, bonding between cylindricalterminals 10 and metal layer 5 of insulating wiring board 3, bondingbetween cylindrical terminals 10 and semiconductor element 8 b, andbonding between implant pins 20 and semiconductor element 8 a areperformed. In addition, implant pins 20 and cylindrical terminals 10 arebonded to each other respectively through plating layer 28.

The heating temperature in the reflow time is preferably not higher than350° C., more preferably in the range of from 250° C. to 330° C. Whenthe heating temperature is higher than 350° C., there is a fear that thesemiconductor elements etc. may be thermally damaged.

External terminals 9 are disposed in predetermined positions of metallayer 5 through the solder or sinter material layer 7 b. When the solderor sinter material layer 7 b is melted or sintered, metal layer 5 andexternal terminals 9 are bonded to each other. Further, cooling plate 1is surrounded by resin casing 2. The internal portion enclosed by resincasing 2 is filled with sealing resin 15. The sealing resin is hardened.In this manner, the semiconductor device is manufactured.

Further another embodiment of the semiconductor device according to theinvention is shown in FIG. 8. In the semiconductor device, implant pins20 are press-fitted into cylindrical terminals 10. Sinter material 29 isapplied to the surfaces of the press-fitting portions of implant pins 20into cylindrical terminals 10 and/or the inner circumferential surfacesof cylindrical terminals 10. When the sinter material is sintered, thepress-fitting portions of implant pins 20 and the inner circumferentialsurfaces of cylindrical terminals 10 are bonded to each other.

A sinter material which can be sintered at a temperature not higher than350° C. is preferably used as sinter material 29. For example, anAg-based sinter material, a Cu-based sinter material, etc. may be usedas sinter material 29. When the sintering temperature is not higher than350° C., the sinter material can be sintered in the reflow process forsoldering the semiconductor elements etc.

Next, another embodiment of a semiconductor device manufacturing methodaccording to the invention will be described as a method formanufacturing the aforementioned semiconductor device.

In the embodiment, sinter material 29 is applied to the innercircumferential surfaces of cylindrical terminals 10 and/or thepress-fitting portions of implant pins 20 into cylindrical terminals 10.Then, implant pins 20 extending from implant board 30 are press-fittedinto cylindrical terminals 10 and the press-fitting depths of implantpins 20 are adjusted. In this manner, the lengths of implant pins 20match up with the distance between semiconductor element 8 b and implantboard 30 and the distance between metal layer 5 and implant board 30.Cylindrical terminals 10 are disposed in predetermined positions ofsemiconductor element 8 b and metal layer through the solder or sintermaterial layer 7 d. Moreover, implant pins 20 extending from implantboard 30 are disposed on semiconductor element 8 a through the solder orsinter material layer 7 e.

The semiconductor device is introduced into a reflow furnace in thisstate so that the solder or sinter material layers 7 a, 7 c, 7 d and 7 eand sinter material 29 are melted or sintered. Thus, through the solderor sinter material layers 7 a, 7 c, 7 d and 7 e, cooling plate 1 andmetal layer 6 of insulating wiring board 3 are bonded to each other. Atthe same time, bonding between the semiconductor elements 8 a and 8 band metal layer 5 of insulating wiring board 3, bonding betweencylindrical terminals 10 and metal layer 5 of insulating wiring board 3,bonding between cylindrical terminals 10 and semiconductor element 8 b,and bonding between implant pins 20 and semiconductor element 8 a areperformed. In addition thereto, implant pins 20 and cylindricalterminals 10 are bonded to each other by sintering of sinter material29.

The heating temperature in the reflow time is preferably not higher than350° C., more preferably in the range of from 250° C. to 330° C. Whenthe heating temperature is higher than 350° C., there is a fear that thesemiconductor elements etc. may be thermally damaged.

External terminals 9 are disposed in predetermined positions of metallayer 5 through the solder or sinter material layer 7 b. When the solderor sinter material layer 7 b is melted or sintered, metal layer 5 andexternal terminals 9 are bonded to each other. Further, cooling plate 1is surrounded by resin casing 2. The internal portion enclosed by resincasing 2 is filled with the sealing resin 15. The sealing resin ishardened. In this manner, the semiconductor device is manufactured.

Thus, a semiconductor device and a method for manufacturing the samehave been described according to the present invention. Manymodifications and variations may be made to the techniques andstructures described and illustrated herein without departing from thespirit and scope of the invention. Accordingly, it should be understoodthat the methods and devices described herein are illustrative only andare not limiting upon the scope of the invention.

REFERENCE SIGNS LIST

-   1: cooling plate-   2: resin casing-   3: insulating wiring board-   4: insulating substrate-   5, 6: metal layer-   7 a, 7 b, 7 c, 7 d, 7 e: solder or sinter material layer-   8, 8 a, 8 b: semiconductor element-   9: external terminal-   10: cylindrical terminal-   15: sealing resin-   20: implant pin-   28: plating layer-   29: sinter material-   30: implant board-   31: insulating substrate-   32, 33: metal layer-   34: insulating wiring board-   35: via hole-   36: bonding material-   51: cooling plate-   52: resin casing-   53: insulating substrate-   54, 55: metal layer-   56: insulating wiring board-   58: semiconductor element-   59: external terminal-   60: bonding wire-   61: sealing resin-   71: insulating substrate-   72, 73: metal layer-   74: via hole-   75: insulating wiring board-   76: implant pin-   79: implant board

What is claimed is:
 1. A semiconductor device comprising: asemiconductor mounting board in which a semiconductor element is mountedon an insulating wiring board, the semiconductor mounting board having acircuit pattern; an implant board in which via holes for electricalconnection are provided in an insulating substrate having a printedwiring, and implant pins, first ends of which are press-fitted into thevia holes and second ends of which are bonded to the semiconductorelement and/or the circuit pattern of the semiconductor mounting boardsuch that there is an electrical connection to the semiconductor elementof the semiconductor mounting board, wherein the implant pins are bondedto the semiconductor element and/or the circuit pattern of thesemiconductor mounting board through cylindrical terminals press-fittedonto the second ends of the implant pins, and a depth with which each ofthe implant pins is press-fitted into corresponding ones of thecylindrical terminals can be adjusted so that total length of theimplant pin and the cylindrical terminal which are press-fitted to eachother match up with a distance between the semiconductor element and/orthe circuit pattern on the semiconductor mounting board and the implantboard.
 2. A semiconductor device according to claim 1, wherein a platinglayer is provided on a surface of a press-fitting portion of each of theimplant pins and/or on an inner circumferential surface of thecylindrical terminal, such that the plating layer bonds the implant pinpress-fitted into the cylindrical terminal to the cylindrical terminalwhen the plating layer is heated and melted.
 3. A semiconductor deviceaccording to claim 1, wherein a sinter material is on a surface of apress-fitting portion of each of the implant pins and/or on an innercircumferential surface of the cylindrical terminal, such that thesinter material bonds the implant pin press-fitted into the cylindricalterminal to the cylindrical terminal when the sinter material is heated.4. A semiconductor device according to claim 1, wherein each of theimplant pins contacts at least 40% of an inner circumference of acorresponding cylindrical terminal in a section perpendicular to theimplant pin in a contact portion between the implant pin and the innercircumferential surface of the cylindrical terminal.
 5. A semiconductordevice according to claim 1, wherein a protruding portion protrudingover an outer circumference of each of the implant pins is provided in apress-fitting portion of the implant pin corresponding to one of thecylindrical terminals by drawing so that the protruding portion can comeinto contact with an inner circumferential surface of the cylinderterminal.
 6. A semiconductor device according to claim 5, wherein avalue obtained by subtracting an inner diameter of each of thecylindrical terminals from a largest diameter of a press-fitting portionof corresponding one of the implant pins which has not yet beenpress-fitted is in the range of from 0 to 0.25 mm.
 7. A semiconductordevice according to claim 1, wherein a straight columnar portion whichis not subjected to drawing is provided in a press-fitting portion ofeach of the implant pins, so that at least a part of the columnarportion can come into contact with an inner circumferential surface of acorresponding cylindrical terminal.
 8. A semiconductor device accordingto claim 7, wherein a value obtained by subtracting an inner diameter ofeach of the cylindrical terminals from a largest diameter of apress-fitting portion of corresponding one of the implant pins which hasnot yet been press-fitted is in the range of from 0 to 0.15 mm.
 9. Asemiconductor device according to claim 1, wherein each of the implantpins has a tapered end on the cylindrical terminal side, so that theimplant pin has a diameter which decreases toward the end.
 10. Asemiconductor device according to claim 1, wherein an innercircumference of each of the cylindrical terminals has a shape whichmatches up with a press-fitting portion of a corresponding implant pin.11. A method for manufacturing a semiconductor device, comprising thesteps of: preparing a semiconductor mounting board in which asemiconductor element is mounted on an insulating wiring board;preparing an implant board in which via holes for electrical connectionare provided in an insulating substrate having a printed wiring andfirst ends of implant pins are press-fitted into the via holes; andbonding second ends of the implant pins of the implant board to thesemiconductor element and/or a circuit pattern of the semiconductormounting board electrically connect the semiconductor element of thesemiconductor mounting board, wherein cylindrical terminals arepress-fitted onto second ends of the implant pins, and a depth withwhich the cylindrical terminal is press-fitted is adjusted so thatlength of the implant pin matches up with a distance between thesemiconductor element and/or a circuit pattern on the semiconductormounting board and the implant board, and the implant pin is bonded tothe semiconductor element and/or the circuit pattern of thesemiconductor mounting board through the cylindrical terminal.
 12. Amethod for manufacturing a semiconductor device according to claim 11,wherein a plating layer is formed on a surface of a press-fittingportion of each of the implant pins and/or on an inner circumferentialsurface of the cylindrical terminal, and wherein the second end of theimplant pin of the implant board abuts against the semiconductor elementand/or the circuit pattern of the semiconductor mounting board throughthe cylindrical terminal and the semiconductor device thus assembled isheated in a reflow furnace in this state to make connection between thesemiconductor element and the insulating wiring board and connectionbetween the cylindrical terminal corresponding to the implant pin andthe semiconductor element and/or the circuit pattern of thesemiconductor mounting board while melting the plating layer to therebyconnect the implant pin and the cylindrical terminal to each other. 13.A method for manufacturing a semiconductor device according to claim 11,wherein a sinter material is applied on a surface of a press-fittingportion of each of the implant pins and/or on an inner circumferentialsurface of the cylindrical terminal, and wherein the second end of theimplant pin of the implant board abuts against the semiconductor elementand/or the circuit pattern of the semiconductor mounting board throughthe cylindrical terminal and the semiconductor device thus assembled isheated in a reflow furnace in this state to make connection between thesemiconductor element and the insulating wiring board and connectionbetween the cylindrical terminal corresponding to the implant pin andthe semiconductor element and/or the circuit pattern of thesemiconductor mounting board while sintering the sinter material tothereby connect the implant pin and the cylindrical terminal to eachother.